EP0957319B1 - Method for operating a closed loop heating or cooling system and a closed loop heating or cooling system - Google Patents

Abstract

A mixer circuit is included and a) is fed from the header of the heat/cold generator, b) is fed regulated from the header of the heat/cold generator and from the return pipe of the direct heating circuit and c) is fed from the return pipe of the direct heating circuit. With a weak load the mixer circuit is solely fed from the return of the direct heating circuit and solely regulated by mixing in the return and in the event of heavy load is fed from the header of the heat/cold generator and the return of the direct heating circuit and is solely regulated by mixing the hot and cold flows.

Description

The invention relates to a method for operating a circulation liquid heating or cooling with a flow and a return line having on the heat / cold generator directly connected direct heating circuit and one with the flow and the Return line of Direktheizkreises connected in parallel, by admixing its return regulated mixer circuit and suitable for its implementation circulation fluid heating or cooling.

If a circulation water heating system with a heat generator two different supply tempered heating circuits, so usually the boiler slid according to the need of higher driven to tempering circuit (direct heating), while the lower tempered Circuit is coupled by a mixing valve to the direct heating circuit (mixer circuit). common is the combination of radiators and underfloor heating in buildings, with one Heat generators are equipped. Usually then the radiators are sliding on operated direct heating circuit and the floor heating at the mixer circuit. Of the Mixer circuit is fed from the supply water of Direktheizkreises.

Such a circulation water heating system is known from DE 35 39 327 A1, which is a A method for controlling a circulating water heater of a central heating system disclosed in the higher of the two flow temperature setpoints of the direct heating circuit and mixer circuit serves as a reference variable for the circulating water heater.

The solution has the further disadvantage that the efficiency of the thermal process as a whole is unsatisfactory. It is known that the lower the efficiency, the higher the efficiency Temperature of the return can be maintained at a given flow temperature. Analogous applies to refrigerators that the return temperature for a given flow temperature as possible should be high.

The object of the invention is therefore to provide a method of the type mentioned and one specify its implementation suitable circulating fluid heating or cooling, with which the temperature of the return in the direct heating circuit at a given boiler flow temperature and given circulating currents as far as possible lowered or kept as high as possible.

a) Der Mischerkreis wird vom Vorlauf des Wärme-/Kälteerzeugers gespeist,

b) der Mischerkreis wird regelbar vom Vorlauf des Wärme-/Kälteerzeugers und vom Rücklauf des Direktheizkreises gespeist,

c) der Mischerkreis wird vom Rücklauf des Direktheizkreises gespeist.

According to the invention the object is achieved in that the following three operating states are possible:

a) the mixer circuit is fed by the flow of the heat / cold generator,

b) the mixer circuit is controllably fed by the flow of the heat / cold generator and by the return of the direct heating circuit,

c) the mixer circuit is fed by the return of the Direktheizkreises.

The method is preferably carried out so that the mixer circuit at low load fed exclusively by the return of the Direktheizkreises and exclusively by Admixed his return and under heavy load from the flow of the heat / cold generator and the return of the Direktheizkreises fed and exclusively by Mixing these heat / cooling flows is regulated, with idling being considered an extreme case of Low load operation and full load as an extreme case of the heavy load operation are to be construed at where the mixing of the direct heating circuit return to zero is regulated.

The conventional method for coupling a mixer circuit to a direct heating circuit is improved with the method according to the invention that, as a rule, a reduction the return temperature of the Direktheizkreises is effected (in refrigeration systems, an increase in the Return temperature), which leads to an increase in efficiency - especially at Condensing boilers - leads. This is achieved by maintaining sufficient temperature in the Mixer circuit first fed return water from the Direktheizkreis in the mixer circuit is used and only at higher temperature demand on supply water or analogous to refrigeration systems with lower temperature requirements. It can be one each suitable fluid can be used.

A circulating liquid heating or cooling suitable for carrying out the process is According to the invention constructed so that the mixer circuit on the input side via a second controllable Three-way mixing valve with the flow line and the return line of the direct heating circuit connected is.

The three-way mixing valves are expediently equipped with limit switches Servomotors actuated.

The servomotors are advantageously mutually locked by limit switch so that only after Opening the first three-way mixing valve driven by a first servomotor Opening the driven by a second servomotor second three-way mixing valve and closing the first three-way mixing valve after closing the second three-way mixing valve is possible.

Advantageously, the first three-way mixing valve in the return from the Mixer circuit branching line a check valve and / or the second three-way mixing valve in the branching off from the inlet of the direct heating circuit line and / or in the branched off from the return of the Direktheizkreises line a check valve upstream and / or in the return of the Direktheizkreises between the terminal of the Flow and the return line of the mixer circuit a throttle valve may be arranged.

The two three-way mixing valves can be functionally combined to form a four-way mixing valve with three inputs and one output and an actuator, wherein in each case only the first and the second or the second and the third input are opened simultaneously could be.

A particularly advantageous industrially prefabricated solution results when the four-way mixing valve Pipe connections for the supply and return of the direct heating circuit, pipe connections for the flow and return of the mixer circuit and the connections of boiler and Mixer circuit to a unit with a flow inlet, a flow outlet, a Return input and a return output of the direct heating circuit and a flow output and a return input of the mixer circuit summarizes. In the unit can also at least one upstream of the inputs of the four-way mixing valve and / or the Advance of the direct heating circuit associated check valve and / or the return of the Direct heating circuit associated throttle valve be integrated into the unit, so that the Assembly unit directly between the boiler and the pumps for the two water or Coolant circuits can be set.

Fig. 1

eine Prinzipdarstellung des erfindungsgemäß an einen Direktheizkreis gekoppelten Mischerkreises einer Umlaufwasserheizung,

Fig. 2

eine Prinzipdarstellung der bisher bekannten Ankopplung,

Fig. 3

ein Beispiel für eine mögliche Schaltung der Stellmotoren der Mischventile des Mischerkreises,

Fig. 4

ein erfindungsgemäßes Vier-Wege-Mischventil in einer symbolhaften Darstellung und

Fig. 5

eine Prinzipdarstellung einer zweiten Variante der Erfindung mit einem Vier-Wege-Mischventil.

Fig. 6

eine Prinzipdarstellung einer Variante ähnlich der von Fig. 5, jedoch mit einem wandhängenden Wärmeerzeuger.

The invention will be explained in more detail below by means of embodiments in the accompanying drawings

Fig. 1

a schematic diagram of the present invention coupled to a direct heating circuit mixer circuit of a circulating water heater,

Fig. 2

a schematic diagram of the previously known coupling,

Fig. 3

an example of a possible circuit of the servomotors of the mixer valves of the mixer circuit,

Fig. 4

an inventive four-way mixing valve in a symbolic representation and

Fig. 5

a schematic diagram of a second variant of the invention with a four-way mixing valve.

Fig. 6

a schematic representation of a variant similar to that of Fig. 5, but with a wall-mounted heat generator.

Fig. 1 shows the invention in a schematic diagram. A pump P1 supplies the n radiators HK, which directly with the boiler flow Q1 of a heat generator WE (boiler) and the Boiler return Q4 are connected (direct heating circuit). The check valve ÜV1 is as Gravity brake for the circular current Q2 formed. At node K1 is a supply current Q3 of the boiler feed water for feeding into the mixer circuit of a floor heating system branched off, which is equipped with a pump P2, the circuit current Q8 in the mixer circuit drives. In the three-way mixing valve MV1 is described in the mode described below the Feed water of mixer circuit blended with return flow Q7 of underfloor heating, so that any intermediate temperature can be generated in the flow water of the mixer circuit can.

To the temperature of the return to the heat generator WE at a given boiler flow temperature and lowering given Q2 and Q8 as far as possible, is at fixed Boiler output, the amount of water in the boiler feed Q1 is kept as small as possible. Since the Circulating current Q2 is considered given is the feed stream Q3 and the return flow Q6 reduce the mixer circuit. This is done by a combination of two three-way mixing valves MV1 and MV2, wherein the mixing valve MV2 and thus the feed of the Mixer circuit with the flow of the direct heating circuit (supply current Q3) and with the return of the direct heating circuit (supply current Q5) is connected.

The mixing valves MV1 and MV2 are to be cascaded in the manner described below:

If the mixing valve MV1 is not fully opened, then the mixing valve MV2 is completely closed
or return current Q7 ≠ 0 ⇒ supply current Q3 = 0, supply current Q5> = 0
and
if the mixing valve MV2 is not fully closed, then the mixing valve MV1 is fully open
or supply current Q3 ≠ 0 ⇒ Return current Q7 = 0, supply current Q5> = 0.

The case
Mixing valve MV1 not fully opened and mixing valve MV2 completely closed
or return current Q7 ≠ 0 and supply current Q3 = 0
represents the light load case
and the case
Mixing valve MV2 not completely closed and mixing valve MV1 fully opened
or supply current Q3 ≠ 0 and return current Q7 = 0
represents the heavy load case.

The case
Mixing valve MV1 fully opened and mixing valve MV2 completely closed
or return current Q7 = 0 and supply current Q3 = 0
is the permissible limit load case.

Excluded is the case
Mixing valve MV not fully opened and mixing valve MV2 not completely closed
or return current Q7 ≠ 0 and supply current Q3 ≠ 0,
since only the mixing valve MV1 is fully opened before the mixing valve MV2 begins to open. When closing the reverse process takes place by first the mixing valve MV2 and then the mixing valve MV1 are closed.

Under full load is the state to understand in which both mixing valves MV1, MV2 complete open or return current Q7 = 0 and supply current Q5 = 0 or supply current Q3 = Return flow Q6 - and under idle the one in which both fully closed or Supply current Q3 = 0 and supply current Q5 = 0 are.

In the light load case, the mixer circuit is thus alone on the mixing of the return flow Q7 regulated by means of the mixing valve MV1. Increases the load request on the Limit load case, so the mixer valve MV1 remains open and the return flow Q7 is Zero. The mixer core MV2 additionally opens and now partially extracts water the flow of Direktheizkreises until the case occurs at full load that the water for the Flow of the mixer circuit is taken solely from the flow of Direktheizkreises.

The prior art of coupling a mixer circuit to a Direktheizkreis means a three- or four-way mixing valve MV1, however, represents FIG. 2.

The pump P1 in turn supplies the n radiator HK, which directly with the heat generator WE (boiler) are connected. In this arrangement, the return flow Q6 is out of the Mixer circuit equal to the supply current Q3 in the mixer circuit. The manipulated variable of the control works for example, by means of a three-point signal "stop-to" on a servomotor M. The Use of other actuators is also given.

Accordingly, the control by means of two servomotors M1 and M2 for the mixer valves MV1 and MV2 of the arrangement according to the invention described in Fig. 1 possible. By the Wiring shown in Fig. 3 of the limit switch of the two servomotors M1 and M2 For example, the above catalog of demands can be achieved and at the same time one can externally integrated actuator for the three-point signal "OPEN-STOP-CLOSE" described above represent.

The specified in Fig. 3 position of the limit switch corresponds to the rest position, ie first a total circuit in an unauthorized state, since none of the servomotors M1 and M2 is in an end position. A first change in the rule game, however, already leads to that one of the allowed cases occurs, so the mixing valve MV1 completely opens and then the downstream mixing valve MV2 opens or the mixing valve MV2 completely closes and then closes the downstream mixing valve MV1.

Compared to the conventional coupling in Fig. 2, the boiler flow Q1 is unchanged Circulating currents Q2 and Q8 in Fig. 1 by the amount of the supply current Q5 lower, which at fixed Flow temperatures and fixed boiler output to the desired effect of lowering the temperature in the boiler return leads. At the same time, the three-position control signal can be present Be used as the arrangement is equivalent to the controlled variable - Flow temperature in the mixer circuit - affects, as in the conventional coupling.

In the following, a device will be described with reference to the symbolic representation in FIG which realizes the method in an economically advantageous manner. It consists in essential from the summary of the two three-way mixing valves to a four-way mixing valve MV with a movable valve body, a drive element M at same Stelverhalten, as described above, three inputs 1, 2 and 3 and an output. 4 It is irrelevant whether it is the mobile body to a hub or Rotation body acts.

Rather, the mixing valve is unique in its function by the following properties characterized:

The residence area of a control element, not shown here is in constant mobility in three points (endpoint I, midpoint, endpoint II) and two areas (area I, area II) subdivided, which analogously to the above definition as full load, heavy load, limit load, Low load and idle can be called. At full load, there is only one connection from input 1 to output 4, under heavy load can slide by movement of the actuator each mixing ratio can be achieved from the inputs 1 and 2 to the output 4, at Limit load is only a connection from input 2 to output 4, at low load can by movement of the actuator sliding each mixing ratio of the inputs 2 and 3 are reached to the output 4 and at idle, there is only one connection of input 3 to the exit 4.

The following Tab. 1 should clearly illustrate the described relationships. load case full load heavy load limit load light load Neutral Input 1 open partly open closed closed closed Entrance 2 closed partly open open partly open closed Entrance 3 closed closed closed partly open open position Endpoint I Area I Focus Area II Endpoint II

Fig. 5 shows the coupling of a circle by means of a thus described four-way mixing valve MV.

The hydraulic system is optional here by a throttle valve DV and two check valves ÜV2 and ÜV3 extended. The throttle valve DV should be in both directions (return flow Q4 positive or negative) increase the pressure difference between the nodes K2 and K3 and can also without moving parts are designed as a baffle plate or other cross-sectional constriction. The Check valves ÜV2 and ÜV3 act as backflow preventer and are said to be parasitic Exclude circular flows.

The arrangement can be advantageously carried out so that outlined by dashed lines in Fig. 5 Individual components to form an assembly with six pipe connections and an actuator spatially are summarized. The arrangement can be as industrially prefabricated accessories be provided and reduces the on-site assembly work considerably.

Finally, FIG. 6 shows a variant with a wall-mounted heat generator WE1, in which the pump P1 is integrated to drive the Direktheizkreises. In case of heavy load, i. at Q3 ≠ 0 and Q5 ≥ 0, a parasitic circuit current through the lines of the boiler flow Q1, To prevent the supply currents Q3 and Q5 and the boiler return Q4, is in Supply current Q5 provided a check valve ÜV4.

Claims (12)

1. A method for operating a closed circuit heating or cooling system with a direct heating circuit (nHK) that comprises a flow pipe and a return pipe and is directly connected to the calorific/frigorific unit, as well as a mixing circuit that is connected in a parallel fashion to the flow pipe and the return pipe of the direct heating circuit (nHK) and the return flow of which is admixed to its own flow, characterized in that the following three operating modes can be realized:

   a) the mixing circuit is supplied by the flow of the calorific/frigorific unit;

   b) the mixing circuit is controllably supplied by the flow of the calorific/frigorific unit and by the return flow of the direct heating circuit (nHK);

   c) the mixing circuit is supplied by the return flow of the direct heating circuit (nHK).
2. The method according to Claim 1, characterized in that the mixing circuit is exclusively supplied by the return flow of the direct heating circuit (nHK) and exclusively controlled by the admixing of its return flow under low loads, and in that the mixing circuit is supplied by the flow of the calorific/frigorific unit and by the return flow of the direct heating circuit (nHK) and exclusively controlled by the mixing of these calorific/frigorific flows under high loads.
3. A closed circuit heating or cooling system with a direct heating circuit (nHK) that comprises a flow pipe and a return pipe, and with a mixing circuit that is connected in a parallel fashion to the flow pipe and the return pipe of the direct heating circuit (nHK) and equipped with a first controllable three-way mixing valve (MV1) for admixing the return flow of the mixing circuit to its own flow, characterized in that the inlet side of the mixing circuit is connected to the flow pipe and the return pipe of the direct heating circuit (nHK) via a second controllable three-way mixing valve (MV2).
4. The closed circuit heating or cooling system according to Claim 3, characterized in that the three-way mixing valves (MV1, MV2) can be actuated by motor operators (M1, M2) that are equipped with limit switches.
5. The closed circuit heating or cooling system according to Claim 4, characterized in that the motor operators (M1, M2) are mutually configured with the aid of these limit switches in such a way that the second three-way mixing valve (MV2) driven by a second motor operator (M2) can only be opened after opening the first three-way mixing valve (MV1) driven by a first motor operator (M1), and the first three-way mixing valve (MV1) can only be closed after closing the second three-way mixing valve (MV2).
6. The closed circuit heating or cooling system according to one of Claims 3-5, characterized in that the first and the second three-way mixing valve (MV1, MV2) are functionally combined into a four-way mixing valve (MV) with three inlets (1, 2, 3) and one outlet (4), as well as an actuating drive, wherein only the first (1) and the second (2) or the second (2) and the third inlet (3) can be opened simultaneously.
7. The closed circuit heating or cooling system according to one of Claims 3-6, characterized in that a check valve (UV2) is arranged upstream of the first three-way mixing valve (MV1) in the line that branches off the return flow of the mixing circuit.
8. The closed circuit heating or cooling system according to one of Claims 3-7, characterized in that a check valve (ÜV3) is arranged upstream of the second three-way mixing valve (MV2) in the line that branches off the flow of the direct heating circuit.
9. The closed circuit heating or cooling system according to one of Claims 3-8, characterized in that a check valve (UV4) is arranged upstream of the second three-way mixing valve (MV2) in the line that branches off the return flow of the direct heating circuit.
10. The closed circuit heating or cooling system according to one of Claims 3-9, characterized in that a throttle valve (DV) is arranged in the return flow of the direct heating circuit (Q4) between the connection of the flow pipe and the return pipe of the mixing circuit.
11. The closed circuit heating or cooling system according to one of Claims 6-10, characterized in that the four-way mixing valve (MV), pipe connections for the flow and the return flow of the direct heating circuit, pipe connections for the flow and the return flow of the mixing circuit and the connections for the direct circuit and the mixing circuit are combined into a module with a flow inlet, a flow outlet, a return flow inlet and a return flow outlet for the direct heating circuit, as well as a flow outlet and a return flow inlet for the mixing circuit.
12. The closed circuit heating or cooling system according to Claim 11, characterized in that at least one check valve (ÜV1, ÜV2, UV3) that is arranged upstream of the inlets of the four-way mixing valve (MV) and/or assigned to the flow of the direct heating circuit and/or a throttle valve (DV) that is assigned to the return flow of the direct heating circuit is also integrated into the module.

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